DESIGN AND EVALUATION OF THE TL-4 MINNESOTA COMBINATION TRAFFIC/BICYCLE BRIDGE RAIL

A combination traffic and bicycle bridge rail was developed and crash tested. The combination bridge rail was constructed with a standard New Jersey safety shaped barrier and special steel panels formed from tubular steel posts and rails, and square vertical spindle bars. Two cables were installed inside the tubular rails to prevent detachment of large pieces of debris from causing hazardous conditions for vehicles and pedestrians below. Although the crash tested bridge rail was constructed using the New Jersey safety shape, it is believed that this combination traffic/bicycle bridge rail could be easily adapted to other safety shape barriers or rectangular parapets with no need for further crash testing. Due to the modular nature of the steel panel sections, the combination traffic/bicycle bridge rail can be repaired very easily following a vehicular impact. Two full-scale vehicle crash tests were performed on Minnesota's combination traffic/bicycle bridge railing. The tests were conducted and reported in accordance with the requirements specified in NCHRP Report No. 350, "Recommended Procedures for the Safety Performance Evaluation of Highway Features" (1993). The safety performance of the combination traffic/bicycle bridge rail was determined to be acceptable according to Test Level 4 of the NCHRP Report No. 350 criteria.